Does turning radiators down make boiler stay on for longer?

[HairyMonster]

I have a Potterton Suprema 50. I'm trying to save money by setting my boiler thermostat to minimum and turning down the radiators to half-maximum. My aim is to have a house temperature which is lower than the minimum thermostat temperature. I've read that this is supposed to work. Can someone please explain this apparent contradiction to me?

On the one hand it makes sense because the radiators and hence the house are cooler so there must be less heat generated which means the boiler isn't working so hard.

On the other hand if the thermostat is set to a certain temperature won't the boiler just stay on until it detects that temperature has been reached irrespective of the radiator settings? If the temperature is never reached because of the low radiator settings then won't the boiler stay on all the time? And if it stays on all the time then where does that extra heat energy go if not to the radiators? Also, if the boiler is on all the time the price will be higher than if I'd set the radiators to max.

I'm confused!

 

[JohnD]

Why don't you use the room thermostat to control the temperature of the house?

The lower you set it the less fuel you will use.

And of course the timer so it is not heated while you are out or in bed.

 

[HairyMonster]

Why don't you use the room thermostat to control the temperature of the house?

I don't have room thermostats. There is only one temperature setting control for the whole property; it is a knob which is attached to the boiler itself. As I have this set to minimum I can only use the radiator valve controls to reduce the temperature further.

 

[Charnwood]

You mention "radiator controls", are they thermostatic controls (TRV)?

The 'stat on the boiler only controls the temperature of the circulated water. The house temperature is not recognised/registered by your boiler because you have no room 'stat.
You really need to get one fitted to have a truly economical, comfortable house, heatwise.

Because your boiler has no way of being advised that no more heat is required if all the rooms are up to temperature and (if they are TRVs) the radiator controls have all closed, it will continue to pump. Not economical, and not good for the system.
Another reason for a room 'stat.

 

[JohnD]

I don't have room thermostats.

Then get one.

A simple one
http://www.screwfix.com/p/drayton-rts8-room-thermostat/46637

or a programmable one that will set different temperatures according to your choice of time of day and day of week.
http://www.plumbworld.co.uk/honeywell-cm907-7-day-761-17210


Your idea of fiddling with the boiler stat does not make sense.